A provisional engagement feature for selectively connecting a fastener such as a screw to a driving tool, the fastener incorporating a head with a recess extending therein and a projection contained within the recess for engagement with a corresponding engagement feature and/or selective locking feature of the driving tool.

A twist-drivable pin assembly includes first and second drivers, each having a driving end which can be received in a bore in the end of a twist-drivable pin, and an opposite end at which torque can be applied. The cross-sectional shape of each of the drivers at its driving end has a first plurality of apexes whose relative locations coincide with the apexes of a regular polygon such as a hexagon. The drivers differ from one another in their cross-sectional shapes at the driving end by virtue of one or more faces of at least one of the drivers between adjacent pairs of apexes having a groove formed in it. Each of first and second twist-drivable pins has a bore extending into it which is defined by a second plurality of apexes arranged as a regular polygon such as a hexagon and which is open at one end.

Screws are provided which have a longitudinal axis and include a threaded shank and a head wherein a socket is formed to be engaged by a wrench and having a pluri-lobed outer profile comprising a series of lobes circumferentially offset and separated by a series of circumferentially offset protrusions of the head. Each protrusion is delimited by two flanks and a front length joining the radially inner ends of the flanks and is convex and symmetrical with respect to a center axis radially oriented with respect to the longitudinal axis. The front length is formed by a center face and two inclined side faces each of which joins the radially inner end of the respective flank with a respective end of the center face, which is oriented orthogonally with respect to the center axis of the protrusion. Pluri-lobed wrenches adapted for use with such screws are also provided.

Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow stick fit engagement of existing standard straight walled drivers in the new system.

A fastener including a shank extending in a direction along a major axis; and a head comprising a hexalobular recess, wherein the hexalobular recess has an inner lobe surface having a radius satisfying

0.234A≤R.sub.i≤2.165A,

wherein A is an outer diameter of the hexalobular recess, and R.sub.i is the radius of the inner lobe surface.

A provisional engagement feature for selectively connecting a fastener such as a screw to a driving tool, the fastener incorporating a head with a recess extending therein and a projection contained within the recess for engagement with a corresponding engagement feature of the driving tool.

The invention relates to a screw, a tool and a system for dental implantology, forming a fixing system and the components thereof to be used in a dynamic pillar assembly. Said dynamic pillar assembly is used in the production of prostheses on dental implants in human implantology in order to fix screws at an angle.

A screw has a screw head and a shank extending downwardly from the screw head. The shank has a threaded segment, a cutting segment, and a tapered segment sequentially arranged downwardly, a thread spirally surrounding an external surface of the shank from the threaded segment to the tapered segment, multiple cutting ribs arranged around the external surface of the shank on the cutting segment of the shank, and multiple chip recesses formed between the cutting ribs. Each of the cutting ribs has a rounded crest to enlarge a drill hole and to reduce a resistance formed between the cutting ribs and the workpiece during drilling. The screw can be easily screwed into the workpiece with less driving force.

A hose adapter may include an outer tube, an inner tube, a hose connector, and a hose. An inner peripheral ring protrudes from the inner periphery of the outer tube while an expanding ring portion protrudes from the outer periphery of an end of the inner tube. The outer periphery of the inner tube further has a first peripheral recess, a second peripheral recess, and a first outer thread, and a first O-ring and a second O-ring are respectively disposed on the first peripheral recess and the second peripheral recess. The inner tube is inserted into the outer tube, and the expanding ring portion is abutted against the inner peripheral ring, and the first O-ring is coupled between the outer tube and the inner tube while the second O-ring and the first outer thread are adapted to pass through and be exposed out of the outer tube.

A screw includes a threaded shank and a head with a first surface. Communicating sockets formed in the first surface include a Pozi-type socket and a drive socket. The drive socket includes rounded portions, arched portions alternating with the rounded portions, and a conical portion connected to the rounded portions and the arched portions to define a first reference line and a second reference line parallel to a central axis of the head. The rounded portions are inclined outwardly from the first reference line, and the arched portions are inclined outwardly from the second reference line. Thus, a first room enclosed by the rounded portions and the arched portions increases gradually towards the first surface. By a combination of the above sockets, the head cooperates with different driving tools for delivering driving force efficiently and is more convenient to use.